Great idea, I wish I'd known about this earlier.
Well, in 1.14 the tooltip for unit names is broken (I should report it on Github), so this is a very basic function to decrease the fontsize if the unit name is too long (part of Better Names, now):

Of course you could get more inventive with this, filtering for how many upper case characters there are, since they take more space. The <span size='small'> font size could probably be slightly enlarged too.

EDIT: BTW, I know you guys use this approach for other elements, too. And sadly some translations extend those strings and then they get cut off, even though they might be more important than this one, for example the side number in Polish. I think this approach would work better.

After a lot of work (40 commits on GitHub!) I can finally announce that I just uploaded version 1.8.0 of the Wesnoth Lua Pack on the 1.14 add-ons server.
While there isn't any new WML tag, a lot of work has been done on the two main GUI debug tags. I also converted the documentation from HTML (I just don't have the time any more to keep up with web programming) to Markdown.

As always, don't forget to report any bug that you find; even better, you can open an issue on GitHub, or make a pull request if you want.

PS. While working on the WLP, I found out that there's another widget that I could've used, called [menu_button]. However, it seems like there's no way to set up a list of values in the dropdown menu, so menu buttons (aka comboboxes) are virtually unusable from Lua. Have I got it right?

That's a very good question... I know it would be possible to use a regular button as a menu button in Lua (create a button whose callback opens a popup menu), but I don't remember how actual menu buttons specified their options. I think there might be a way but I'm not sure.

IIRC, it's just with [option] tags under [menu_button] if you want to set them up from the dialog config. The actual C++ implementation uses a vector of configs... not sure if that was ever exposed to Lua.

Creator of Shadows of Deception (for 1.12) and co-creator of the Era of Chaos (for 1.12/1.13).SurvivalXtreme rocks!!!
What happens when you get scared half to death...twice?

So if that's correct, it would mean you can use menu buttons from Lua but probably can't alter their list of options once the dialog is being shown (you can only alter them before it's shown by editing the config).